Field of the Invention
The present invention relates to a determination apparatus for determining the type of a recording medium and an image forming apparatus using the same.
Description of the Related Art
In order for an image forming apparatus to properly adjust a usage amount of toner or ink or properly reproduce a gradation characteristic of an original image, image forming conditions need to be adjusted in accordance with characteristics (grammage, thickness, surface property and the like) of a recording medium. Japanese Patent Laid-Open No. 2004-107030 proposes detecting the grammage (weight per unit of area) of a recording medium using ultrasonic waves. Japanese Patent Laid-Open No. 2002-182518 proposes detecting a surface property of a recording medium using a CMOS sensor.
If the type of a recording medium is detected using inventions described in Japanese Patent Laid-Open No. 2004-107030 and Japanese Patent Laid-Open No. 2002-182518 and image forming conditions are adjusted in accordance with the detected type, the image forming apparatus will be able to achieve an image quality of a certain level. However, in the inventions described in Japanese Patent Laid-Open No. 2004-107030 and Japanese Patent Laid-Open No. 2002-182518, variations in a detection value due to the moisture content of a recording medium is not considered, and thus there is room for further improving detection accuracy for the type of a recording medium.